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<head><meta charset="utf-8"><title>dangling rc::Weak and unsized types · t-lang · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/index.html">t-lang</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html">dangling rc::Weak and unsized types</a></h3>

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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221026670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221026670">(Dec 27 2020 at 22:48)</a>:</h4>
<p>Turns out there is a surprising interaction between unsized types and <code>Weak::new</code>: <a href="https://github.com/rust-lang/rust/pull/80407">https://github.com/rust-lang/rust/pull/80407</a>.<br>
<span class="user-group-mention" data-user-group-id="1977">@T-lang</span>  This is hitting stable in 4 days, so if we want to revert something we'd have to act quickly.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221027012" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Daniel Henry-Mantilla <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221027012">(Dec 27 2020 at 22:58)</a>:</h4>
<p>Could we delay the stabilization for 6 weeks / next stable? Just to give people more time to think about how to best handle that; it would be a pity to have to rush a decision in 4 days, especially when those 4 days happen during new year's eve and people may be busy with holidays / family? <span aria-label="grimacing" class="emoji emoji-1f62c" role="img" title="grimacing">:grimacing:</span></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221027105" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221027105">(Dec 27 2020 at 23:01)</a>:</h4>
<p><span class="user-mention" data-user-id="120791">@RalfJ</span> <span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span> for reverting and delaying for a cycle, to give people non-holiday time to process.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221027252" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221027252">(Dec 27 2020 at 23:05)</a>:</h4>
<p>(Not saying that we should absolutely revert, more that I have no objection to reverting to give people time.)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221027744" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221027744">(Dec 27 2020 at 23:19)</a>:</h4>
<p>If you want to revert please prepare a PR or what needs to get reverted and ping me ASAP, expectation is to prepare stable artifacts tomorrow.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028115" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028115">(Dec 27 2020 at 23:28)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> Around, by any chance?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028125">(Dec 27 2020 at 23:29)</a>:</h4>
<p>Yeah I'm on right now</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028504" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028504">(Dec 27 2020 at 23:38)</a>:</h4>
<p>Got some time to talk through the implications of this issue? You mentioned that you don't think it needs to be reverted, and your descriptions of the implications do sound potentially reasonable. But I'm hesitant to just let the passage of time make that call.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028571">(Dec 27 2020 at 23:40)</a>:</h4>
<p>I built a revert patch</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028573" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028573">(Dec 27 2020 at 23:40)</a>:</h4>
<p>but it doesnt apply on the <code>stable</code> branch</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028574" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028574">(Dec 27 2020 at 23:40)</a>:</h4>
<p>the stable branch doesnt have the unsized methods</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028576" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028576">(Dec 27 2020 at 23:40)</a>:</h4>
<p>is that already what will be released on Thu?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028584">(Dec 27 2020 at 23:41)</a>:</h4>
<p>I'm perfectly fine letting it wait another cycle for publish, as that gives time to understand what exactly is being implied by the stabilization</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028586">(Dec 27 2020 at 23:41)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/pull/74160">https://github.com/rust-lang/rust/pull/74160</a> was merged on Oct 3, it should be on stable, right? <em>confused</em> did git not update the other branches?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028630" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028630">(Dec 27 2020 at 23:42)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> Can you elaborate on why <code>align_of_val</code> is required in the second of the four possibilities you mentioned? Why do you need to know alignment to be able to go backwards to the reference count?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028654" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028654">(Dec 27 2020 at 23:43)</a>:</h4>
<p><span class="user-mention silent" data-user-id="132829">Christopher Durham</span> <a href="#narrow/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types/near/221028584">said</a>:</p>
<blockquote>
<p>I'm perfectly fine letting it wait another cycle for publish, as that gives time to understand what exactly is being implied by the stabilization</p>
</blockquote>
<p>Yeah, in an ideal world, I'd love to have you come to a lang design meeting and talk about this in more depth.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028723">(Dec 27 2020 at 23:45)</a>:</h4>
<p><span class="user-mention" data-user-id="239881">@Josh Triplett</span> because of alignment: <code>#[repr(C)] ( usize, usize, T )</code> will have padding between the refcounts and the <code>T</code> if alignment of <code>T</code> is greater than that of <code>usize</code></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028727">(Dec 27 2020 at 23:45)</a>:</h4>
<p>that stable branch is oitated I think</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028728">(Dec 27 2020 at 23:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> what's the branch to base the patch on?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028731" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028731">(Dec 27 2020 at 23:46)</a>:</h4>
<p>So in order to find the refcounts from a <code>*const T</code> to the <code>T</code> part, you need the alignment of <code>T</code> to determine how much padding is present</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028777">(Dec 27 2020 at 23:46)</a>:</h4>
<p>The third option is to avoid that requirement by moving the padding to the front</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028798">(Dec 27 2020 at 23:48)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> Oh, I see; I wasn't thinking of the case where there are alignment requirements <em>larger</em> than <code>usize</code>. That makes sense.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028854">(Dec 27 2020 at 23:49)</a>:</h4>
<p>patch prepared at <a href="https://github.com/rust-lang/rust/pull/80422">https://github.com/rust-lang/rust/pull/80422</a></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028860" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028860">(Dec 27 2020 at 23:49)</a>:</h4>
<p>Beta branch</p>



<a name="221028862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028862">(Dec 27 2020 at 23:49)</a>:</h4>
<p>The idea of just moving the padding to the front and the <code>usize</code> to right behind the T, and storing a pointer to the T, makes sense and doesn't seem too disruptive...</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028863">(Dec 27 2020 at 23:49)</a>:</h4>
<p>but no idea what branch it should go on, so this is master and needs to be cherry-picked elsewhere</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028871" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028871">(Dec 27 2020 at 23:50)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> okay that seemed too new^^ but can be done</p>



<a name="221028905"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028905" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028905">(Dec 27 2020 at 23:50)</a>:</h4>
<p>But we should land on master first</p>



<a name="221028907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028907">(Dec 27 2020 at 23:50)</a>:</h4>
<p>Well or in parallel</p>



<a name="221028923"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028923" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028923">(Dec 27 2020 at 23:51)</a>:</h4>
<p>I'll pick it up in the stable promotion tomorrow</p>



<a name="221028939"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221028939" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221028939">(Dec 27 2020 at 23:51)</a>:</h4>
<p>oh now I force-pushed to the master branch... okay</p>



<a name="221029008"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029008" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029008">(Dec 27 2020 at 23:53)</a>:</h4>
<p>I think nothing further is needed from you wrt to patches, <span class="user-mention" data-user-id="120791">@RalfJ</span> to be clear, I can apply the existing one before release on Thursday</p>



<a name="221029022"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029022" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029022">(Dec 27 2020 at 23:53)</a>:</h4>
<p>okay, now I also prepared <a href="https://github.com/rust-lang/rust/pull/80423">https://github.com/rust-lang/rust/pull/80423</a></p>



<a name="221029024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029024">(Dec 27 2020 at 23:53)</a>:</h4>
<p>feel free to use it or close and re-do yourself if that works better</p>



<a name="221029068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029068">(Dec 27 2020 at 23:54)</a>:</h4>
<p>Yeah that's fine, either works</p>



<a name="221029095"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029095" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029095">(Dec 27 2020 at 23:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> I think, despite the mention in <a href="https://github.com/rust-lang/rust/pull/80407">https://github.com/rust-lang/rust/pull/80407</a> that the revert might not be necessary, we should go ahead and revert so that people don't have to worry about it over the holidays.</p>



<a name="221029096"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029096" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029096">(Dec 27 2020 at 23:55)</a>:</h4>
<p>the force push on <a href="https://github.com/rust-lang/rust/issues/80422">#80422</a> will have canceled the r+</p>



<a name="221029100"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029100" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029100">(Dec 27 2020 at 23:55)</a>:</h4>
<p>Let's take our time figuring out the long-term implications of stabilizing this.</p>



<a name="221029103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029103">(Dec 27 2020 at 23:55)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> Thank you <em>very</em> much for catching this.</p>



<a name="221029104"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029104" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029104">(Dec 27 2020 at 23:55)</a>:</h4>
<p>Yes I agree we should not rush, especially over holidays</p>



<a name="221029107"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029107" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029107">(Dec 27 2020 at 23:55)</a>:</h4>
<p><span class="user-mention silent" data-user-id="239881">Josh Triplett</span> <a href="#narrow/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types/near/221028654">said</a>:</p>
<blockquote>
<p>Yeah, in an ideal world, I'd love to have you come to a lang design meeting and talk about this in more depth.</p>
</blockquote>
<p>I'd be honored to participate, and since I'm still on break for another 4 weeks, don't have any schedule conflicts if you want to have me in to discuss.</p>



<a name="221029155"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029155" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029155">(Dec 27 2020 at 23:56)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> We've cancelled the lang meetings over the holidays, so the next lang design meeting would be Wednesday, 2021-01-06.</p>



<a name="221029156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029156">(Dec 27 2020 at 23:56)</a>:</h4>
<p><span class="user-mention silent" data-user-id="239881">Josh Triplett</span> <a href="#narrow/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types/near/221029103">said</a>:</p>
<blockquote>
<p><span class="user-mention silent" data-user-id="132829">Christopher Durham</span> Thank you <em>very</em> much for catching this.</p>
</blockquote>
<p>It wasn't me, it was @mahkoh that brought it up originally</p>



<a name="221029172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029172">(Dec 27 2020 at 23:57)</a>:</h4>
<p><a href="https://github.com/rust-lang/rfcs/issues/3041#issuecomment-751254472">https://github.com/rust-lang/rfcs/issues/3041#issuecomment-751254472</a></p>



<a name="221029227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029227">(Dec 27 2020 at 23:59)</a>:</h4>
<p>FWIW, I suspect that requiring static alignment of DSTs is <em>probably</em> fine.</p>



<a name="221029230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029230">(Dec 27 2020 at 23:59)</a>:</h4>
<p>But it sounds like there are plenty of workarounds, too.</p>



<a name="221029235"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029235" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029235">(Dec 27 2020 at 23:59)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> What's your preferred email for calendar invites?</p>



<a name="221029312"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029312" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029312">(Dec 28 2020 at 00:00)</a>:</h4>
<p><a href="mailto:therealcad97@gmail.com">therealcad97@gmail.com</a> if it's google, <a href="mailto:cad97@cad97.com">cad97@cad97.com</a> otherwise</p>



<a name="221029639"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221029639" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221029639">(Dec 28 2020 at 00:10)</a>:</h4>
<p>I'm out for the day, feel free to push to my branch(es) if needed</p>



<a name="221030531"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221030531" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221030531">(Dec 28 2020 at 00:35)</a>:</h4>
<p><span class="user-mention" data-user-id="120791">@RalfJ</span> Thank you for the timely help.</p>



<a name="221030670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221030670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221030670">(Dec 28 2020 at 00:39)</a>:</h4>
<p><span class="user-mention" data-user-id="132829">@Christopher Durham</span> Do you go by "Chris" or "Christopher" or something else? (Just writing out the description of the design meeting.)</p>



<a name="221030877"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221030877" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221030877">(Dec 28 2020 at 00:44)</a>:</h4>
<p>I sent out the invite for the 2021-01-06 meeting.</p>



<a name="221031685"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/213817-t-lang/topic/dangling%20rc%3A%3AWeak%20and%20unsized%20types/near/221031685" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Christopher Durham <a href="https://rust-lang.github.io/zulip_archive/stream/213817-t-lang/topic/dangling.20rc.3A.3AWeak.20and.20unsized.20types.html#221031685">(Dec 28 2020 at 01:06)</a>:</h4>
<p><span class="user-mention" data-user-id="239881">@Josh Triplett</span>  Just Christopher is fine</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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